1. Field of the Invention
The present invention relates to woven materials that have a myriad of desired two- and three-dimensional shapes by virtue of their being constructed by varying the density and/or direction of the warp and/or weft fibers or yarns, as well as their angle of contact, at will during the mechanical weaving process.
2. Description of the Prior Art
The following patent summaries are indicative of the prior art.
In U.S. Pat. No. 5,421,128, there is disclosed a curved inflated, tubular beam consisting of braided fibers and axial fibers on an elastomeric barrier. The construction can be accomplished on a short, straight mandrel. The curvature along the beam can be varied to suit the design needs. The angle of the braid in the bias fibers determines the inflated curvature when axial fibers situated within the braid along the inside of the curvature constrain the elongation on the inside of the curvature. The curved shape can be reinforced by having tape cemented to the outside of the inflated tube. While very small and very large tubes can be perfected for a range of inflation pressures and beam strengths, the preferred embodiment is a 12 and three quarter-inch diameter tube, 60 feet long forming an arch for a tent 30 feet wide and 24 feet high.
In U.S. Pat. Nos. 5,229,177 and 5,082,701, there are disclosed a multi-directional, light-weight, high-strength interlaced material and a method of making the material. This material comprises continuous flat unidirectional flat ribbons, which have been precut from an impregnated fiber reinforced-matrix composite tape so as to have a substantially greater width than thickness, that are interlaced in over-and-under relationship in 0 degree and 90 degree directions into the form of a continuous, multi-directional seamless tube. The tube may be cut into tubular sections, which then are subjected to temporary heat and pressure so that the matrix fuses the interlaced ribbon to form an integral tube. The elongated seamless tube may also be cut into planar sections and used to form integral members of planar or contoured construction. The integral members may be formed of a single layer of the interlaced material, or of laminated construction from multiple layers of interlaced material, with the ribbons of each layer either extending parallel, at an angle other than 0 degrees/90 degrees, aligned, or offset, with respect to the ribbons in the other layer(s). The formed members may have interlaced ribbons of different types and/or contain different types of fibers in different sections of the members, to provide the members with different structural characteristics.
In U.S. Pat. No. 5,070,914, there is disclosed a triaxial textile fabric for use as a reinforcing textile fabric for a composite material wherein the modulus of elasticity is made isotropic and which can be readily deformed into a three-dimensional configuration with out causing special changes in orientation angles and a process by which such a textile fabric can be easily produced. The fabric comprises a large number of oblique yarns extending in a radial direction from the center of the textile fabric, and a circumferential yarn woven spirally in a circumferential direction between the oblique yarns. Each adjacent ones of the oblique yarns are interlaced with each other and the circumferential yarn is woven between the thus interlaced oblique yarns such that such interlacing may appear between each adjacent coils of the spirally woven circumferential yarn. Such an interlacing step takes place after insertion of the circumferential yarn and before an upward and downward movement of the alternate oblique yarns.
Structural members of high strength that are used in various commercial applications have normally been constructed of metal. Recently, both flexible and rigid plastic composite materials have been successfully used as substitutes for metal in these structural members. Even more recently, fibrous manufactured materials, sometimes with a plastic matrix material for fiber bonding, have been used to further reinforce these metal substitutes in high-strength structural members. This substitution has resulted because fiber-reinforced plastic composite materials are lighter, stronger, less expensive, less subject to corrosion, and more impact resistant than traditional metals, such as steel, titanium, and aluminum.
In forming these fiber-reinforced materials, the fibers, or yarns made up of multiple fibers, can be arranged in parallel next to one another, extending longitudinally in one direction. For further structural strength, the resultant material can then be impregnated with a plastic matrix. The resultant material, whether impregnated or not, can then be arranged in layers with the fibers or yarns in these additional layers being oriented in a direction that is different from that of the previous layer. As a result, the fiber-reinforced material can have additional strength.
Unfortunately, the production of these materials is both labor-intensive and expensive. The multiple manufacturing steps involved in making each layer, then overlaying them on each other, as well as the process steps involved in impregnating the materials with plastic matrices, make the overall process costly. In addition, it is difficult to make these materials into the different, complex shapes that are necessary to form structural members of varied design and shape largely because of the stresses and tension placed upon the individual fibers or yarns in the arrays when they are deformed against one another while the shaping process occurs.
As an alternative, the fibers or yarns can be woven into materials that can be used as reinforcement. However, the angle at which these fibers contact each other is severely limited by the manufacturing apparatus with their being no ability to vary the angle of contact throughout the material during an automated manufacturing process. Again, the shapes that can be made by these weaving methods are severely constrained because the limited angle of fiber contact and the stresses and tensions between adjacent and interlaced fibers or yarns do not allow the flexibility necessary to deform the material to a desired shape. In fact, the weaving must normally be done by hand in order to be able to vary the characteristics of the material enough to form the necessary different shapes. Thus, while current weaving techniques can improve the production process somewhat, the manufacture of these materials remains very laborious and far too expensive for anything other than military and commercial aerospace and aircraft applications.
Thus, there exists a need to develop methods that will allow cost-effective, automated manufacture of fiber-reinforced structural members and structures, in general, so that the range of commercial applications to which these materials can be applied is expanded. While the prior art provides some improvements in the manufacturing process for the production of interwoven materials, the limited angle of fiber or yarn contact and the inability to vary this angle at will using the current methods, the inability to continuously vary the widths and densities of the fibers or yarns during automated manufacturing, and the resultant stresses and tensions between adjacent and interlaced fibers or yarns in these materials do not allow the flexibility necessary to deform the interwoven materials into desired shapes. Therefore, the ability to continuously vary the fiber or yarn widths and densities while changing the angle of contact at will during an automated manufacturing process is still lacking in the present state of the art.
Accordingly, it is an object of the present invention to provide a cost-effective method of manufacture of fiber-reinforced structural members and structures, in general. Yet another object of the present invention is to construct an interwoven material in which the angle of contact of the warp and weft fibers or yarns can be continuously varied at will during an automated manufacturing process. Still another object of the present invention is to continuously vary the widths of the fibers or yarns during automated manufacture as desired. A further object of the present invention is to thus continuously vary the densities of the fibers or yarns during manufacture as desired. Yet a further object of the present invention is to be able to efficiently produce interwoven materials of various shapes by automated manufacture that can be used in making structural members and structures, in general.